AB0792 Hip involvement in spondyloarthritis: analysis of associated factors
Authors: H. Tbini, M. Slouma, S. Rahmouni, A. Abdennadher, K. Amri, Y. Mallat, L. Metoui, R. Dhahri, I. Gharsallah, B. Louzir
Journal: Annals of the Rheumatic Diseases (2022)

Background Hip involvement occurs in about one-third of patients with spondyloarthritis (SA) [1]. It can be responsible for significant disability and functional impairment. Objectives This study aimed to assess the associated factors with hip involvement in SA. Methods We conducted a cross-sectional study, including 165 patients with SA diagnosed according to Assessment of SpondyloArthritis international Society (ASAS) criteria over a period from 2017 to 2021. Demographic, clinical, biological and radiographic data were collected. We compared following parameters assessed at the time of diagnosis of coxitis: Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Ankylosing Spondylitis Disease Activity Score (ASDAS-CRP), modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), Bath Ankylosing Spondylitis Radiology Index (BASRI), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). We used logistic regression analysis to identify factors associated with hip involvement in SA. Results A total of 165 Patients were enrolled (121 men and 44 women), the mean age was 46.13 ± 13.07 years. The mean age of disease onset was 35.01 ± 12.55 years. The average diagnostic delay was 37.54 ± 50.51 months. The average disease duration was 10.91 ± 6.94 years. Eighty seven percent of patients had axial spondyloarthritis, 72% had extra-articular manifestations. Mean ESR and CRP values were 37.49 ± 28.1 mm and 30.14 ± 43.55 mg/L, respectively. Mean BASDAI and ASDAS-CRP values were 4 ± 1.8 and 3.09 ± 1.13, respectively. Hip involvement was noted in 60 patients (36.4%). It was bilateral in 75% of cases (n=45). A total number of affected hips was 105. Following parameters were significantly higher in patients with hip involvement: age over 40 years old (73.3 vs 56.3%, p=0.030), symptoms duration over 10 years (60% vs 40.2%, p=0.015), elevated CRP (87.9% vs 73.7%, p=0.036), radiographic sacroiliitis (95% vs 82.7%, p=0.023), frequency of pulmonary involvement (25.0% vs 11.4%, p:0.023), frequency of osteoporosis (20.0% vs 8.6%, p:0.034), BASMI (3.71 vs 1.65, p&lt;0.001), BASRI spine (5.97 vs 2.91, p&lt;0.001), and mSASSS (16.24 vs 5.80, p:0.001). However, no association was found between HLA-B27 and hip involvement (50% vs 28.6%, p=0.099). A multivariable logistic regression model showed that age over 40 years (OR=2.688 [1.020 - 7.083], p=0.045), radiographic sacroiliitis (OR=5.656 [1.007 - 31.769], p=0.049), and very high disease activity (ASDAS-CRP≥3.5) (OR=5.328 [1.774 - 16.002], p=0.003) were independently associated with hip involvement in SA. Conclusion Our study showed that age, symptoms duration, radiographic sacroiliitis, extra-articular manifestations, axial structural damage, elevated CRP, and very high disease activity were associated with hip involvement. These finding suggest that the control of disease activity and inflammation may prevent the onset of hip involvement. There are controversial findings regarding the association between HLA B27 gene and hip involvement [2]. References [1]Vander Cruyssen B, Vastesaeger N, Collantes-Estévez E. Hip disease in ankylosing spondylitis. Curr Opin Rheumatol. 2013 Jul;25(4):448-54. [2]Chen HA, Chen CH, Liao HT, Lin YJ, Chen PC, Chen WS, Chou CT. Factors associated with radiographic spinal involvement and hip involvement in ankylosing spondylitis. Semin Arthritis Rheum. 2011 Jun;40(6):552-8. Disclosure of Interests None declared